Conestat alfa is a manmade form of a protein called C1 esterase inhibitor that occurs naturally in the bloodstream and helps control swelling in the body. People with a condition called hereditary angioedema do not have enough of this protein. Hereditary angioedema can cause attacks of swelling and symptoms such as stomach problems or trouble breathing.

Conestat alfa is used to treat angioedema attacks in people with hereditary angioedema. Conestat alfa is for use in adults and children who are at least 13 years old.

Conestat alfa may also be used for purposes not listed in this medication guide.

You should not use conestat alfa if you are allergic to rabbits or rabbit products (meat, fur, pelt).

Follow all directions on your prescription label. Do not use conestat alfa in larger or smaller amounts or for longer than recommended.

Conestat alfa is injected into a vein through an IV. You may be shown how to use an IV at home. Do not self-inject this medicine if you do not understand how to give the injection and properly dispose of used needles, IV tubing, and other items used to inject the medicine.

Conestat alfa is a powder medicine that must be mixed with a liquid (diluent) before using it. If you are using the injections at home, be sure you understand how to properly mix and store the medicine. Ask your pharmacist what type of diluent can safely be mixed with conestat alfa powder.

Wash your hands before mixing the medicine or preparing your injection.

Read all patient information, medication guides, and instruction sheets provided to you. Ask your doctor or pharmacist if you have any questions.

After mixing conestat alfa, store in the refrigerator and use within 8 hours. Do not freeze.

Mixed medicine should be used right away if you keep it at room temperature.

Conestat alfa doses are based on weight. You may need to use two vials of conestat alfa powder to make up a single dose. Carefully follow all mixing instructions provided with your medicine.

Each single-use vial (bottle) of this medicine is for one use only. Throw away after one use, even if there is still some medicine left in it after injecting your dose.

This medicine must be injected slowly, and the IV infusion should take about 5 minutes to complete.

A single dose of conestat alfa is usually enough to treat an angioedema attack. You may need to use a second dose if your symptoms do not get better after just one dose.

Store the unmixed dry powder in a refrigerator or in a dark cool place. Keep the medicine protected from light and do not allow it to freeze. Throw away any unused vial after the expiration date on the label has passed.

Usual Adult Dose for Hereditary Angioedema:

Less than 84 kg: 50 international units/kg IV injection once over approximately 5 minutes; may repeat once if symptoms persist.
84 kg or more: 4200 international units IV injection once over approximately 5 minutes; may repeat once if symptoms persist.

Maximum dose: Not to exceed 4200 international units per dose or 2 doses per 24 hours

Usual Pediatric Dose for Hereditary Angioedema:

13 Years or Older:
Less than 84 kg: 50 international units/kg IV injection once over approximately 5 minutes; may repeat once if symptoms persist.
84 kg or more: 4200 international units IV injection once over approximately 5 minutes; may repeat once if symptoms persist.

Maximum dose: Not to exceed 4200 international units per dose or 2 doses per 24 hours

You should not use conestat alfa if you are allergic to it, or:

• if you are allergic to rabbits or rabbit products (meat, fur, pelt); or

• if you have ever had a life-threatening allergic reaction to conestat alfa or to another C1 esterase inhibitor (such as Berinert or Cinryze).

To make sure conestat alfa is safe for you, tell your doctor if you have:

• coronary artery disease (hardened arteries); or

• a history of stroke or blood clot.

This medicine is not expected to harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It is not known whether conestat alfa passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

Conestat alfa is not approved for use by anyone younger than 13 years old.

Since conestat alfa is used when needed, it does not have a daily dosing schedule. Call your doctor promptly if your symptoms do not improve after using this medicine.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Get emergency medical help if you have signs of an allergic reaction: rash or hives; chest tightness, wheezing, difficult breathing; blue-colored lips or gums; fast heartbeats; feeling like you might pass out; swelling of your face, lips, tongue, or throat.

Conestat alfa may cause serious side effects. Call your doctor at once if you have:

• sudden numbness or weakness (especially on one side of the body);

• sudden severe headache, slurred speech, problems with vision or balance; or

• pain, swelling, warmth, or redness in one or both legs.

Common side effects of conestat alfa may include:

• headache;

• diarrhea; or

• nausea.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Other drugs may interact with conestat alfa, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.